Engineers designed columns that feature concrete-filled, fiber-reinforced polymer tubes (CFFT). The columns have been subjected to explosive testing and showed no signs of external damage, the scientists say.

Echevarria and Zaghi designed and constructed 10 test bridge columns: five with the conventional reinforced concrete design and five with the experimental CFFT design. Each column is one-fifth to scale.

Two of the test columns—one with the conventional design and one with the experimental design—will serve as controls and will not be exposed to fire or explosives.

Working with the U.S. Army Corps of Engineers Research and Development Center in Mississippi, four of the test columns (two conventional and two experimental) were subjected to explosive testing over a period of eight weeks.

In the explosive testing, the experimental design showed no outward signs of the damage. Here, cracking is seen in a conventional column after blast loading.

The experimental CFFT columns showed no outward signs of damage, even after being exposed to a significant level of explosives, according to Zaghi.

Next, another group of four columns will be shipped to a laboratory in upstate New York where they will undergo lengthy exposure to extreme fire.

After the fire test is complete, all 10 columns will be sent to the Structural Research Laboratory on the Storrs campus where force will be applied to the column ends until the point of failure, or when the columns are crushed.

Data gathered from all three tests will help the team determine how well the new bridge column design could hold up in extreme conditions.

Researchers are also looking into techniques that could help officials quickly assess damaged bridge columns. Under Christenson's supervision, the team is working on a special hammer that could be used after an explosion, fire, or earthquake to test whether the bridge is safe enough for traffic.

Four columns will undergo exposure to extreme fire; all 10 columns will be subjected to pressure until the point of failure.

The research is supported by the University of Connecticut's HS-STEM Program, which is administered by the Center for Resilient Transportation Infrastructure and funded by the U.S. Department of Homeland Security Science and Technology Directorate/Office of University Programs.